Various methods for predicting the future conditions of a wireless communication channel are known in the art. For example, a channel prediction method is described by Duel-Hallen et al., in “Long Range Prediction of Fading Signals: Enabling Adaptive Transmission for Mobile Radio Channels,” IEEE Signal Processing Magazine, (17:3), May, 2000, pages 62-75, which is incorporated herein by reference. The method computes the linear Minimum Mean Squared Error (MMSE) estimates of future fading coefficients based on past observations.
Channel prediction is sometimes used for adaptive transmission. For example, an application of the method proposed by Duel-Hallen et al. to adaptive modulation is described by Hu et al., in “Adaptive Modulation Using Long Range Prediction for Flat Rayleigh Fading Channels,” Proceedings of the IEEE International Symposium on Information Theory, Sorrento, Italy, Jun. 25-30, 2000, which is incorporated herein by reference.
As another example, U.S. Pat. No. 5,541,955, whose disclosure is incorporated herein by reference, describes an adaptive data rate modem, which supports multiple data rates. The modem incorporates an adaptive data rate encoder and an adaptive data rate decoder. Soft decision metrics of the decoder are used to provide an estimate of the signal-to-noise ratio (SNR). An optional predictor receives the SNR estimate from the decoder and predicts the future signal-to-noise ratio, to determine the desired data rate for the modem.